1. Field of the Invention
The present invention relates to an electronic component series which comprises a tape-like receiving member for receiving a plurality of electronic components distributed along the longitudinal direction thereof, and more particularly, it relates to an electronic component series in which a cover tape is heat-sealed to a receiving tape provided with concavities for receiving the respective electronic components.
2. Description of the Prior Art
U.S. Pat. No. 4,298,120 discloses various examples of electronic component series which are of background interest to the present invention.
FIG. 13 is an exploded perspective view partially showing a conventional electronic component series. The electronic component series 1 shown therein comprises a receiving tape 3, in order to receive a plurality of electronic components 2. The receiving tape 3 is formed with a plurality of receiving concavities 4 which are distributed along its longitudinal direction. When the receiving tape 3 is made of, e.g., a sheet of thermoplastic resin, the receiving concavities 4 can be formed by embossing the same. The receiving tape 3 is also formed with a plurality of feeding perforations 5 which are distributed along the longitudinal direction thereof.
In order to retain the electronic components 2 in the receiving concavities 4, a cover tape 6 is arranged along the longitudinal direction of the receiving tape 3, to cover the respective receiving concavities 4. The cover tape 6 is made of thermoplastic resin, and regions 7 close to both side edges thereof, which regions 7 are shown in a cross-hatched manner in FIG. 13, are heated so that the cover tape 6 is heat-sealed to the receiving tape 3.
The aforementioned sealing process is generally performed by utilizing a sealing iron 9 which contains a heater 8, as shown in FIGS. 14 and 15. The sealing iron 9 has a pair of contact surfaces 10 which extend linearly in parallel with each other. The sealing iron 9 brings the contact surfaces 10 in contact with portions of the cover tape 6 close to both side edges thereof from above the electronic component series 1 which is intermittently fed, thereby to seal the regions 7 of the cover tape 6 as shown in FIG. 13 to the receiving tape 3.
FIGS. 16 to 18 are plan views showing three examples of electronic component series which are obtained by sealing cover tapes 6 to receiving tapes 3 by the sealing iron 9 as shown in FIGS. 14 and 15. Referring to FIGS. 16 to 18, cross-hatched parts of respective side edges of the cover tapes 6 show heat-sealed portions 11. Further, regions defined by one-dot chain lines are contact/heated regions 12 to be in contact with the aforementioned contact surfaces 10.
The electronic component series 1a, 1b and 1c as shown in FIGS. 16 to 18 respectively are standarized in size to be commonly processed by a specific automatic apparatus, and regularly set are pitches for arranging receiving concavities 4a, 4b and 4c and feeding perforations 5, respective widths of the receiving and cover tapes 3 and 6. However, the receiving concavities 4a, 4b and 4c are varied in size, in order to receive different-sized electronic components 2a, 2b and 2c.
The electronic component series 1a as shown in FIG. 16 is provided with relatively small receiving concavities 4a. In this case, the heat-sealed portions 11 are formed to be substantially equal in width to the contact/heated regions 12.
The electronic component series 1b as shown in FIG. 17 is provided with relatively large receiving concavities 4b, which are particularly wide in the cross direction. In this case, no heat-sealed portion 11 is formed in portions of the contact/heated regions 12 under which the receiving concavities 4b are located, and the heat-sealed portions 11 are increased and decreased in width at regular intervals.
The electronic component series 1c as shown in FIG. 18 is provided with receiving concavities 4c which are exactly interposed between the two contact/heated regions 12. Therefore, the heat-sealed portions 11 are originally formed in correspondence to the contact/heated regions 12, whereas, undesirably, the same inwardly extend in regions between respective adjacent receiving concavities 4c due to the configuration of the sealing iron 9 as shown in FIGS. 14 and 15. This is because heat radiated from the contact surfaces 10 and their vicinity of sealing iron 9 is transferred to relatively wide regions of the cover tape 6. Thus, heat sealing is inevitably performed in portions other than the contact/heated regions 12 of the cover tape 6, which portions are in contact with the receiving tape 3. Such inward extension of the heat-sealed portions 11 also takes place in the electronic component series 1a and 1b as shown in FIGS. 16 and 17, and hence the heat-sealed portions 11 cannot be maintained constant in width in any of the electronic component series 1a, 1b and 1c, regardless of the sizes of the receiving concavities.
When the heat-sealed portions 11 are varied in width as in the aforementioned examples shown in FIGS. 16 to 18, the following problems are caused in steps of supplying the electronic components 2a, 2b and 2c through such electronic component series 1a, 1b and 1c in practice:
In general, an electronic component series is fed in its longitudinal direction through the feeding perforations while, simultaneously, its cover tape is upwardly moved to be separated from the receiving tape. Thereafter the electronic components retained in the receiving concavities are taken out from the same to be supplied to a prescribed printed circuit board or the like.
In view of the aforementioned step of separating the cover tape from the receiving tape, the force required for such separation is not constant with respect to the longitudinal directions of the cover tapes 6 in the electronic component series 1a to 1c as shown in FIGS. 16 to 18, particularly in 1b and 1c. In other words, a greater force is required to separate the cover tapes 6 from the receiving tapes 3 in regions where the heat-sealed portions 11 are wider, while the cover tapes 6 are separated with smaller force in regions where the portions 11 are narrower. Thus, the forces required for such separation are periodically or non-periodically increased and decreased in all of the electronic component series 1a to 1c. Due to such changes in separation force, the electronic component series 1a, 1b and 1c are undulated in the portions from which the cover tapes 6 are separated, whereby the receiving tapes 3 vibrate in the vertical direction. Such undulations will be intensified as separation speeds are increased.
The undulations as hereinabove described may undesirably bring out the electronic components 2a, 2b and 2c from the receiving concavities 4a, 4b and 4c of the receiving tapes 3 or change the directions thereof after separation of the cover tapes 6, leading to obstructions in the steps of supplying the electronic components 2a, 2b and 2c.